Terry Pratchett’s books are always so funny and playful. There are several different strands of characters that recur in different books. This one is one of the ones that follows the lives of small-town witches.
They’re looking for a third witch (their previous apprentice having recently married the king) and they have an idea for who would be a good apprentice. Unfortunately, she’s moved to the big city to pursue her dream of being an opera singer.
This book follows the concept of “Phantom of the Opera” but in the wacky, alternative world that is Terry Pratchett’s head. The apprentice, Agnes, is an exceptionally talented singer, but very large (the proverbial “fat lady” of the opera) and therefore, isn’t getting much in the way of parts. Another girl who started at the same time as Agnes is lacking in all talent, but has a rich family that donated to the opera house and is also beautiful, so she’s getting a lot of attention.
There’s a phantom in the opera that moves things around and demands access to a box every performance. But lately he’s started to get in a murderous mood and people are dying.
Christine and Agnes switch rooms, which is how Agnes receives the secret nighttime singing lessons from the phantom. For the performance, they have Christine sing quietly while Agnes sings loudly behind the curtain.
Meanwhile, the phantom continues to kill people, and the witches are in town to lure Agnes back. They come into the opera house and track down the phantom and pull Agnes out of the soul-crushing world of opera and everyone lives happily ever after. As indeed, is the Terry Pratchett way.